For ajax data loading with group and data work for me using,
$arrFinal = array(array("name"=>"My shiny group 1",
"children"=>array(array("id"=>1,"name"=>"My shiny item 11"),array("id"=>2,"name"=>"My shiny item 12"))
),array("name"=>"My shiny group 2",
"children"=>array(array("id"=>1,"name"=>"My shiny item 21"),array("id"=>2,"name"=>"My shiny item 22"))
)
);
die(json_encode(array("result" => $arrFinal)));
if formatResult: ratioFormatResult then,
function ratioFormatResult(row) {
// Here, you will get both group ("My shiny group 1") as well as data("My shiny item11") as row .
}
To make group selectable use id field along with name in group.